Question: Jessica is 5 times as old as Umaima and is also 12 years older than Umaima. How old is Jessica?
Answer: We can use the given information to write down two equations that describe the ages of Jessica and Umaima. Let Jessica's current age be $j$ and Umaima's current age be $u$ $j = 5u$ $j = u + 12$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $j$ is to solve the second equation for $u$ and substitute that value into the first equation. Solving our second equation for $u$ , we get: $u = j - 12$ . Substituting this into our first equation, we get the equation: $j = 5$ $(j - 12)$ which combines the information about $j$ from both of our original equations. Simplifying the right side of this equation, we get: $j = 5j - 60$ Solving for $j$ , we get: $4 j = 60$ $j = 15$.